Microlipoinjection is a process in which fat is taken by a cannula from one spot in the body and reinjected in another place in the body. Microlipoinjection has also been known as liposuction with fat transfer, fat grafting or fat transplantation. In general, microlipoinjection is performed to treat divots and scar indentations from trauma to the face or body, such as may occur as a secondary effect of domestic trauma, surgery or infection. Microlipoinjection can also be used to treat the effects of the loss of the subcutaneous layer of fat due to the normal aging process, either alone or in combination with facelift and fat grafting techniques. Microlipoinjection can also be used for providing filler to reapproximate weakened vocal cords, fill sinuses, or partially close incompetent valves.
In addition, every mass of fat in the human body has with it a varying number of adult stem cells. These stem cells are the precursor to healthy fat cells. In addition to readily developing into normal fatty tissue, they have a limited ability to differentiate into different tissue. When placed in fat they will divide several times into mature fat cells and more adult stem cells. These stem cells are an important part of a tissue harvest.
Up to about 1990, there were few artificial filler substances available to surgeons. Accordingly, surgeons used human bone, collagen and fat as fillers. However, the use of fat was not very successful, because the instruments and techniques were not sufficiently refined. For example, 50% of the fat may not have lived through the transplantation process. As a result, surgeons would need to implant more fat than would be required if all of the fat survived the process, or the transplantation process would have to be repeated multiple times or both.
More recently, a number of filler substances, such as Restylane Hyaluronic Acid, Collagen, Fibril, ePTFE (Teflon®), Hylan B Gel, Artecol, BioBlastique and have been used. These substances have proved effective at filling small areas, but the cost for larger areas has become prohibitive. For this reason, as well as interest in the “natural substance” concept, surgeons and their patients have again looked at using fat as a filler.
With the renewed interest in using fat as a filler, techniques have been refined to provide a better fat graft “take” with revascularization. However, the instruments and devices conventionally available to perform the procedure remain clumsy and ill-suited for the procedure.
Commonly available liposuction handles and cannulas often have severe drop-offs, blind pockets, or other discontinuities in the tissue pathway. These discontinuities result in an instrument that is difficult or impossible to clean. In addition, two piece instruments featuring separable handle and cannulas can make cleaning the instrument even more difficult where at least some portion of the tissue pathway is formed by the handle. In particular, discontinuities in the interior pathway of the cannula and/or handle creates drop-offs or blind pockets that are difficult or impossible to clean. For example, tissue can become impacted in such areas, posing a risk of contamination. Typical systems that feature separable cannulas and handles can also be expensive to manufacture, because of the fittings required to effect a secure connection between the cannula and handle.
In addition to drop-offs, blind pockets and other discontinuities along the length of a tissue transfer channel, typical cannulas often include blind pockets at their tip, which are difficult or impossible to clean. The shape of the outer surface of cannulas also can be such that the practitioner using the instrument must exercise special care to avoid damage to tissue that is not to be removed from the body.
Accordingly, it would be desirable to provide a cannula and/or a cannula and handle system that was easy to clean. In addition, it would be desirable to provide a system in which a cannula could be secured to a handle in a secure fashion, and that was economical to produce. It would also be desirable to provide a cannula that removed tissue to be transferred efficiently, and with reduced damage to that tissue and to neighboring tissue.